Heat sink



FIG. 1 is a perspective view of a heat sink depicting a first embodiment of a new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is a perspective view of a heat sink depicting a second embodiment of a new design;

FIG. 9 is a front elevational view thereof;

FIG. 10 is a rear elevational view thereof;

FIG. 11 is a left side elevational view thereof;

FIG. 12 is a right side elevational view thereof;

FIG. 13 is a top plan view thereof; and,

FIG. 14 is a bottom plan view thereof.

The broken line portion of the drawings is included to show unclaimed subject matter only and forms no part of the claimed design. 

CLAIM The ornamental design for a heat sink, as shown and described. 